# Square and Cube Roots Quiz Set 009

### Question 1

How many 4 digit numbers are their whose squares end in 2?

A

0.

B

2.

C

3.

D

4.

Soln.
Ans: a

It is not possible for the square of any number to end in 2, 3, 7 or 8. Hence the answer is 0.

### Question 2

What is the least number that should be subtracted from 0.0509 to make it a perfect square?

A

0.05.

B

0.06.

C

0.02.

D

0.03.

Soln.
Ans: a

We know that 0.03 = \$√0.0009\$, so by inspection we can see that 0.0509 - 0.05 will give us 0.0009.

### Question 3

What is the value of \$√{(11 - 2√3) × (11 + 2√3)}\$?

A

\$√109\$.

B

9.

C

10.

D

√3.

Soln.
Ans: a

By inspection, we can easily see that the formula (a - b) × (a + b) can be used to simplify like this: \$√{(11)^2 - (2√3)^2}\$, which is same as \$√{121 - (2^2 × 3)}\$, which is same as \$√{121 - 12}\$ = \$√109\$.

### Question 4

If \$√2\$ = 1.41, then what is the value of \${√2}/5\$ − \$4/{√2}\$?

A

-2.546.

B

-2.665.

C

-2.412.

D

-2.049.

Soln.
Ans: a

The given expression can be simplified to \${{(√2)^2} - 5 × 4}/{5 × √2}\$, which is same as \${2 - 20}/{5 × √2}\$, which is same as \${-18/{5 × √2}\$. Rationalizing, we get \${-18/{5 × √2} × {√2/√2}\$ which gives \${-18√2}/10\$ which = -2.546.

### Question 5

What is cube root of 0.000729?

A

0.09.

B

0.729.

C

0.81.

D

0.081.

Soln.
Ans: a

We can see that 0.09 × 0.09 × 0.09 = 0.000729, so cube root is 0.09. This Blog Post/Article "Square and Cube Roots Quiz Set 009" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2020-02-07. Published on: 2016-04-20